1. Field of the Invention
The inventions disclosed and taught herein relate generally to voltage converters; and more specifically relate to step-down voltage converters for power supplies.
2. Description of the Related Art
U.S. Pat. No. 5,748,422 discloses a “power latch circuit for a computer is improved by the expansion of an activate control circuit to include overvoltage protection circuitry. The activate control circuit is responsive to either an activate input circuit or a feedback latch circuit to activate an activating transistor which in turn activates a series transistor providing power from a DC electric power source through a voltage regulating circuit to the computer, which is programmed to turn itself off by activating a deactivate transistor to deactivate the activating and series transistors. In the improved circuit, the activate control circuit includes elements for activating the activating transistor and series transistor in a switching mode when the output voltage of the series transistor does not exceed a fixed limit voltage and in a voltage regulating mode when the output voltage of the series transistor exceeds the fixed limit voltage, whereby an increase in the output voltage of the series transistor beyond the fixed limit voltage is reduced. The activate control circuit further deactivates a hold-off transistor during activation of the activating and series transistors, regardless of the mode of operation.”
U.S. Pat. No. 7,259,609 discloses a “clamping circuit containing a transistor and a current amplifier. The transistor is designed to turn on when the voltage at a node exceeds (falls below) a specified upper (lower) level. The current amplifier is designed to draw substantial amount of current when the transistor is turned on to clamp the voltage at the node to the desired level.”
SMPS Design Extends Universal Input to 690 Vac, by Luca Difalco, which was published by Power Electronics Technology, on Oct. 1, 2007, discusses a “quasi-resonant flyback converter uses high-voltage emitter-switched bipolar transistors to achieve the wide input voltage range needed to power digital electric-energy meters in both residential and industrial applications.”
Other examples of power converter systems include “A cycloconverter or a cycloinverter converts an AC waveform, such as the mains supply, to another AC waveform of a lower frequency, synthesizing the output waveform from segments of the AC supply without an intermediate direct-current link”, according to a Wikipedia article entitled Cycloconverter, as available on Dec. 8, 2009.
The inventions disclosed and taught herein are directed to an improved method and system for stepping down relatively high voltage to a lower voltage.